INFICON TM-400 Thin Film Deposition Monitor - Manual (Page 67)

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TM-350/400 Operating Manual
Chapter 10
Computer Interface
10.1 General
The various computer interfaces of the INFICON TM-350/400 Deposition Monitors
permit complete remote control using a personal computer. There are three types
of computer interfaces offered. The TM-350/400 comes standard with an RS-232
serial interface. Both RS-485 and IEEE-488 interfaces are available as options.
10.2 RS-232 Serial Interface
The standard RS-232 serial interface of the TM-350/400 allows one monitor to be
connected to any other device with an RS-232 serial interface. The RS-232
interface port is the D9P connector on the rear panel of the monitor. The pin layout
is shown in
Figure 3-7 on page 3-10 and Table 3-4 on page 3-10 lists pin signal
assignments, including a definition of whether the signal is an input or an output of
the TM-350/400.
The TM-350/400 acts as DTE, and accordingly the 9-pin connector has ‘plug’ pins.
It can be used with a DCE or a DTE host cable connection providing the sense of
the RxD/TxD data lines and the control lines is observed. Pin 2 ‘TxD’ transmits data
from the TM-350/400 to the host; pin 3 ‘RxD’ receives data from the host. Pin 7
‘CTS’ is a control output signal, and pin 8 ‘RTS’ is a control input signal.
In this implementation, pin 7 ‘CTS’ means what is says, namely, this is an output
control line, and when the TM-350/400 asserts this control line ‘true’ the host can
transmit to the TM-350/400. On the other hand, pin 8 ‘RTS’ is not quite what it may
seem because this is a signal input to the TM-350/400, and it is intended that the
host should assert this line ‘true’ only when the TM-350/400 is allowed to transmit
data to the host. The TM-350/400 does not generate an RTS ‘request-tosend’ as
such for the host PC, so the host should assert pin 8 true whenever the
TM-350/400 is allowed to transmit to the host, without being asked to do so.
The TM-350/400’s RS-232 port is automatically set up to operate with the following
specifications: 9600 Baud, 8 Bit data, No Parity, 1 Stop bit
10.3 RS-485 Serial Interface
The optional RS-485 serial interface of the TM-350/400 allows connection of up to
32 separate devices equipped with RS-485. The RS-485 serial interface is also
ideal in electrically noisy environments and in applications where long cables are
required. The RS-485 port of the TM-350/400 is the same D9P connector on the